Contents

Design and development

It was originally ordered as the LB-10A (a single-tail modification of the Keystone LB-6), but the Army dropped the LB- 'light bomber' designation in 1930.

Although the performance of the B-3A was hardly better than that of the bombers flown at the end of World War I, it had come a long way. In terms of its safety, it was far superior to its oldest predecessors.

Operational history

The B-3A was the last biplane operated by the US Army; it remained in service until 1940. A few years after it was first produced, the introduction of all-metal monoplanes rendered it almost completely obsolete.

Variants

LB-10

The last of the 17 LB-6s ordered (S/N 29-27) was converted with a re-designed single fin and rudder and two 525 hp R-1750E engines. Delivered to Wright Field on 7 July 1929, it was wrecked on 12 November 1929.

LB-10A

This version used Pratt and Whitney R-1690-3 Hornet engines and was slightly smaller, both wingspan and fuselage. a total of 63 were ordered (S/N 30-281/343). It was re-designated as the B-3A before any deliveries were made, and the final 27 were built as B-5A.

B-3A

36 delivered as B-3A (S/N 30-281/316). The first aircraft was delivered in October 1930.